Motion converting means



April 1956 L. TARWATER MOTION CONVERTING MEANS Filed June 18, 1951 FIG.

INVENTOR LAWSON TARWATER ATTORNEYS United States Patent MOTION CONVERTING MEANS Lawson Tarwater, Redlands, Califl, assignor to Tarwater Railway Supply Co., a corporation of California Application June 18, 1951, Serial No. 232,137

1 Claim. (Cl. 74-56) This invention has to do with motor-driven hammers or tamping machines.

An object of the invention is to provide a novel, electrical hammer or tamping machine having improved operating characteristics over electrical tamping machines presently in use with which I am familiar.

Another object is to provide a power-driven hammer or tamper having novel and efficient means for transmitting power from the motor to the hammer of the machine. In this connection it is an object to provide a simplified drive mechanism for translating the rotary motion of a driveshaft into reciprocatory rectilinear motion of a hammer shaft or bar.

A further object is to provide a power-driven hammer which delivers a sharp blow without damage or undue Wear to the motor, bearings, gears, and other parts of the mechanism.

More particularly it is an object to provide an improved cam mechanism and construction associated with the hammer or striker bar of the tamping machine.

These and other objects will be apparent from the drawing and the following description.

Referring to the drawing:

Fig. 1 is a sectional elevational the invention;

Fig. 2 is a plan view on a smaller scale;

Fig. 3 is an inverted sectional view in the plane of line 3--3 of Fig. 1;

Fig. 4 is a developed view of the cam track; and

- Fig. 5 is an exploded elevational view on an enlarged scale showing the liner and a portion of the striker.

More particularly describing the invention, reference number 11 generally designates the power-driven hammer or tamping machine and 12 indicates the upper portion of a tamping tool which would be detachably mounted therein and operated by the machine.

The tamping machine is made up of a plurality of view of a tool embodying sections of housing or casing. At the upper end of the tool is a motor housing 14 on which are mounted handles 15 and 16 by bolts 17.

A gear housing 22 is mounted directly below the motor housing and secured thereto by bolts 23. A hearing plate 25 and a cam housing 26 are positioned in that order below the gear housing and secured thereto by the bolts 23. An end housing 28 is mounted at the lower end of the cam housing, being secured thereto by means of flanges 29 and 30 and bolts 31. Below this the machine is provided with a bushing retainer 33 which is detachably secured in place by means of flanges 34 and 35 and bolts 36.

At the upper end of the tool within the motor housing 14 is a suitable electric motor and this may be provided with conventional wiring and a switch 41 for controlling it. The motor 40 has a depending motor shaft 42 which extends into the space 43 within the gear housing, being received within a bearing 44 mounted in the upper end of that housing. This shaft carries gear teeth 42a at its lower end which mesh with a gear wheel 45 2,741,924 Patented .Apr. 17, 1956 Ice fixedly mounted on .or :formed on countershaft 46. This latter shaft is supported at'its upper end in a bearing '48. mounted in arecess 49: in the: gear housing 22 and 'at its lower endin abearing .51 mounted in the bearing .plate 25.

A driveshaft 54 is mounted in. axial alignment with-the motor. shaft and driven by means .of -.a :pinion 551- keyed thereto at its upper end and retained by nut 56 which meshes with a gear section 57 on the countershaft 46.

The driveshaft is supported near its upper end in a double radial thrust bearing 60 and at its lower end within a bore 62 formed in what will be termed a striker, indicated generally by 64.

The cam housing is hollow, being formed with an interior cylindrical wall 66. Near its upper end the housing is provided with an annular space 67 and radially inward of this is a lesser bore or coun-terbore 68 in which is mounted the aforementioned bearing 60. A liner or guide sleeve 70 extends partway up the wall 66 and is fixedly mounted in any conventional way in the bore 66. The striker 64 is adapted for reciprocal motion within the chamber in the housing 26 and it fits slidably within the liner 70, being shown in up position on thedrawing. It is yieldably urged outwardly by a powerful compression spring 71 partially received in annular space 67. Keys 78 on the flange portion 78 of the striker slidably fit slots or guideways 70' in liner 70 as shown in Fig. 5.

The lower portion of the striker comprises a tubular section 72 which is received slidably within a bushing 73 at the upper end of a bore 74 through housing section 28 and within a second bushing 76 within the same bore. Above the section 72 the striker is flanged at 78 and above this is a cam section 79 having an outward cylindrical wall surface 80. The upper end of section 79 includes a centrally apertured wall 81 which supports a bearing 82 receiving shaft 54. The under surface of wall 81 is formed to provide a cam track 84, the profie of which is shown in Fig. 4.

The driveshaft is provided with a cam follower 85 which rides on the cam track, the follower being mounted upon a threaded pin 86 which is threadedly mounted in the driveshaft radially thereof.

In the operation of the device the driveshaft 54 is rotated by the motor through the medium of the gears in the gear housing 22. The cam follower 85 rotates with the shaft riding on the cam track 84 thereby serving to lift the striker against the action of the compression spring 71 and release the same once during each revolution. Each time the cam follower passes the high point of the cam the spring 71 forcibly urges the striker outwardly to deliver a hammer blow against a tool 12 which is received within a bushing 88 in bushing retainer 33. In order to relieve any pressure build-up which might otherwise occur in the lower end of the striker in the space 90 and in the space 91 within the housing 26, the bushing 73 is provided with several axially extending passages 92 which communicate with an annular space 93 around the lower end of the striker and in turn with the space 90 through ports 94 in the striker.

While I have illustrated and described a preferred form of my invention, I contemplate that various changes and modifications can be made without departing from the invention, the scope of which is indicated by the following claim.

I claim:

In a motor-driven hammer, a housing, a motor in said housing, a driveshaft mounted for rotation in said housing, gear means operatively connecting said shafts, a striker member, said housing providing a cylindrical chamber and a cylindrical bore of reduced diameter therebelow, said striker member including a lower section slidably received in said bore and an upper section slidably received in said chamber, said driveshaft being rotatably References Cited in the file of this patent received in said lower section, said upper section providing UNITED STATES PATENTS a downwardly facing can-1 track, a cam follower on said driveshaft extending radially thereof and engaging said 408383 Lacavolene et a1 1889 cam track, said lower section of said striker member and 5 504912 Demonet 1893 said housing providing an annular space in said bore, 1310575 P i et a1 July 1919 said lower section havinga port communicating with said 2110957 f 1938 space, said housing having a vent passage extending from 3 3 2 i ,a g an. the lower portion of said cyllndrical chamber to said 2,548,411 Vache p 11 1951 annular space, and spring means yieldably urging said 1 striker member toward the lower end of said housing. 

